Support device for heart valve prostheses

ABSTRACT

A support device for implanting a stentless heart valve prosthesis having three leaflets adapted for coapting and defining three corresponding commissures is disclosed. The support device includes a shaft defining a manipulation axis, the shaft having a proximal portion and a distal portion, and three support formations integrally formed and extending from the proximal end of the shaft, the support formations angularly distributed about the manipulation axis of the shaft, such that each of the support formations correspond to locations of each of the commissures of the stentless heart valve prosthesis. The shaft includes a connection portion flexibly connecting the shaft and the support formations to permit a displacement of the manipulation axis with respect to the support formations. The shaft, the plurality of support formations and the connection portion are integrally formed from a single tubular element.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Application No. 12425070.5filed Apr. 4, 2012, which is herein incorporated by reference in itsentirety.

TECHNICAL FIELD

This invention relates to cardiac valve prostheses and in particular tosupport devices therefor for assisting in the implantation of suchdevices.

BACKGROUND

Cardiac valve prostheses can essentially be divided into two basiccategories, namely “mechanical” valve prostheses, in which the bloodflow through the valve is controlled by one or more obturatorsconstituted by rigid bodies mounted so as to be able to oscillate ortilt in a rigid support, and “biological” valve prostheses, in whichblood flow is controlled by valve leaflets formed of biological tissue.The biological valve leaflet material, which is subject to treatment(stabilization) to render it biologically inert, can be derived from anatural cardiac valve taken from an animal (for example a pig) or can beformed from biological tissue other than valve tissue (for example,bovine pericardium). Biological valve prostheses may in turn take theform of “stented” valves, where the valve leaflets are mounted on arigid or slightly flexible stent or armature, and “unstented,” or“stentless,” valves.

EP-A-0 515 324 and U.S. Pat. No. 5,713,953 disclose various embodimentsof stentless cardiac valve prostheses, including embodiments where thebiological material is replaced (either partially or completely) with anartificial/synthetic material such as a micro-porous and/or compositesynthetic material, for example polyurethane. Stentless valve prosthesesmay exhibit as a whole characteristics of deformability that offerfunctional advantages due to a great similarity to the anatomy ofnatural valves. On the other hand, because stentless valves do nomaintain a consistent shape, they may be somewhat more challenging toimplant properly. Optimal implantation of a stentless valve, either byconventional or minimally-invasive surgical techniques, may involvepositioning the prosthesis at the implantation site (e.g., an aorticsite) using a holder device. Such a holder may support the prosthesisduring production, packaging and/or implantation of the prosthesis bythe surgeon. Holder devices may include a support or “grip” hub adaptedfor connection to a manipulation handle. The surgeon can thus locate aprosthesis (held by the holder) at the implantation site and properlyorient it with respect to the native valve anatomy.

One such exemplary holder is shown in US 2008/0262603 A1, which includesa grip element and a plurality of arms for supporting a prosthetic heartvalve at an intermediate position between the commissures. The holdersshown in the prior art however are either quite complex in constructionor design. Additionally, the manipulation capabilities of these holdersmay often be not completely satisfactory.

SUMMARY

The present invention, according to various embodiments, provides asupport device for stentless heart valve prostheses, which is easy tomanufacture and offers better manipulation performances compared toknown devices. In various exemplary embodiments of the invention, theseproblems are solved by a support device for stentless valve prostheseshaving the features of the appended claims.

According to one embodiment, the problem is solved by a support devicefor a stentless heart valve prosthesis including: a shaft defining amanipulation axis, a plurality of support formations for a stentlessvalve prosthesis, a connection portion flexibly connecting the shaft andthe support formations to permit a displacement of the manipulation axiswith respect to the support formations, wherein the shaft, the pluralityof support formations and the connection portion are formed in a singlepiece from a tubular element.

Additionally, preferred embodiments of the invention include, forexample:

Embodiment 1: a support device for stentless heart valve including: ashaft defining a manipulation axis, a plurality of support formationsfor a stentless valve prosthesis, and a connection portion flexiblyconnecting the shaft and the support formations to permit a displacementof the manipulation axis with respect to the support formations, whereinthe shaft, the plurality of support formations and the connectionportion are formed in a single piece from a tubular element.

Embodiment 2: the support device of embodiment 1, wherein the tubularelement is made of a shape memory material.

Embodiment 3: the support device of either embodiment 1 or 2, whereinthe tubular element is made of nitinol.

Embodiment 4: the support device of any of the previous embodiments,wherein the plurality of support formations includes support arms whichare cut in the tubular element and shaped so that they protrude therefrom, the support arms departing from a hub provided on the tubularelement adjacent to the connection portion.

Embodiment 5: the support device of embodiment 4, wherein the supportarms include a first portion extending radially away from themanipulation axis and a second portion, bent with respect to the firstportion, which extends substantially parallel to the manipulation axis.

Embodiment 6: the support device of embodiment 5, wherein the firstportion of each support arm also extends in an axial direction of thesupport device.

Embodiment 7: the support device of any of embodiments 4 to 6, includingthree support arms arranged with an even angular spacing around themanipulation axis.

Embodiment 8: the support device of any of the previous embodiments,wherein the connection portion consists of a helical track cut in thetubular element.

Embodiment 9: the support device of any of the previous claims, whereinthe shaft comprises a free end at which connection formations configuredfor coupling the support device to a manipulation tool are provided.

Embodiment 10: the support device of any of embodiments 4 to 7, furtherincluding at least one through hole provided on the tubular member at aradial position corresponding to that of a supporting formationassociated thereto.

Embodiment 11: the support device of embodiment 10, wherein the at leastone through hole is provided on the hub.

Embodiment 12: the support device of embodiment 5, wherein each supportarm includes a first eyelet located at a position between the first andsecond portions and a second eyelet at a free end of the second portion.

Embodiment 13: the support device of Embodiment 5 or Embodiment 10,further comprising at least one through hole located on the firstportion of each supporting arm.

Embodiment 14: a combination of a stentless heart valve prosthesis and asupport device according to any of embodiments 1 to 13.

Embodiment 15: the combination of embodiment 14, wherein the stentlessheart valve prosthesis is an aortic valve prosthesis including threecoapting valve leaflets and three commissures, each coupled to acorresponding support formation.

While multiple embodiments are disclosed, still other embodiments of thepresent invention will become apparent to those skilled in the art fromthe following detailed description, which shows and describesillustrative embodiments of the invention. Accordingly, the drawings anddetailed description are to be regarded as illustrative in nature andnot restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the attachedfigures, provided purely by way of non limiting example, and wherein:

FIG. 1 is a perspective view of a support device for stentless heartvalve prostheses according to various exemplary embodiments,

FIG. 2 is a perspective view corresponding to that of FIG. 1 but showingvarious deformed conditions,

FIG. 3 is a perspective view of a support device according to variousembodiments coupled to a biological stentless heart valve prosthesis andshown in one possible deformed condition,

FIG. 4 is a perspective view of a support device according to variousembodiments coupled to a biological stentless heart valve prosthesis andshown in another possible deformed condition,

FIG. 5 is a perspective view of an example of a manipulation tool whichcan be coupled to a support device according to various embodiments ofthe invention, and

FIGS. 6 and 7 are perspective views showing further exemplaryembodiments of the support device for stentless heart valve prostheses.

While the invention is amenable to various modifications and alternativeforms, specific embodiments have been shown by way of example in thedrawings and are described in detail below. The intention, however, isnot to limit the invention to the particular embodiments described. Onthe contrary, the invention is intended to cover all modifications,equivalents, and alternatives falling within the scope of the inventionas defined by the appended claims.

DETAILED DESCRIPTION

In the following description, numerous specific details are given toprovide a thorough understanding of embodiments. The embodiments can bepracticed without one or more of the specific details, or with othermethods, components, materials, etc. In other instances, well-knownstructures, materials, or operations are not shown or described indetail to avoid obscuring aspects of the embodiments.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases “in oneembodiment” or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments. Theheadings provided herein are for convenience only and do not interpretthe scope or meaning of the embodiments.

In FIG. 1, reference number 1 identifies as a whole a supporting devicefor stentless heart valve prostheses according to various exemplaryembodiments. The supporting device 1 includes a shaft 2 defining amanipulation axis X1, a plurality of support formations 4 intended forsupporting a stentless heart valve prosthesis and a connection portion 6flexibly connecting the shaft 2 and the supporting formations 4, whichin turn depart form a hub 7 immediately adjacent to the connectionportion 6. All the components mentioned above are formed in a singlepiece from a tubular element T which is subject to a number of cuttingand forming operations. In various embodiments the tubular element T hasa circular cross section.

In various embodiments, in a distal portion 8 of the tubular element T,the shaft 2 and the connection portion 6 include a helical track 10 cutinto the tubular member T. In various embodiments, in a proximal portion9 of the tubular element T, the hub 7 has a plurality of radial holeslocated thereon. In exemplary embodiments, such holes may be arranged inpairs oriented along the direction of the manipulation axis X1. In someembodiments, adjacent pairs of radial holes 12 may be axially staggered.

In the present description, the terms “distal” and “proximal” are usedwith reference, so to say, to the implantation site, i.e., proximalbeing a location close to the implantation site (and corresponding tothat of a valve prosthesis coupled to the support device 1), whiledistal being a location away from the implantation site.

In various embodiments, on the distal portion 8, in particular at a freeend of the shaft 2, there may be provided a number of couplingformations 14, 16, which may be in the form of longitudinal slits 14 orin the form of radial holes 16 or both. Such coupling formations areintended to provide a connection, e.g., of the snap-fit type, of thesupport device 1 to a manipulation tool which will be described in thefollowing. In other embodiments, no such formations 14 and 16 arepresent, so that the coupling between the manipulation tool and thesupport device may be achieved by relying upon, e.g., an interferencefit.

In various embodiments, on a second portion of the tubular element T thesupport formations 4 are cut and formed so that each supportingformation is shaped as a supporting arm including a first portion 18extending radially away from the manipulation axis X1 and a secondportion 20, which is bent with respect to the first portion 18 and whichextends substantially parallel to the manipulation axis X1. In someembodiments, such as those depicted in the figures, the first portions18 may be formed so to extend also axially away from the shaft 2.

Furthermore, in various embodiments, each supporting formation 4 mayinclude a first eyelet 22 located at a position corresponding to that ofthe bend between the first portion 18 and the second portion 20 and asecond eyelet 24 located at a free end of the second portion 20. Inother embodiments, each supporting arm 4 may include only one eyelet,either being the eyelet 22 or 24. In various embodiments, the eyelets22, 24 may be oriented so that respective axes Y22, Y24 thereof areincident to the manipulation axis X1.

As shown in the exemplary embodiment of FIG. 2, the supporting device 1includes three supporting arms 4, which are disposed with even angularspacing (i.e., 120 degrees) around the manipulation axis X1. As shown,the supporting arms are capable of flexing inwards and outwards in aradial direction. FIG. 2 also shows, in phantom lines, two possibledeformed conditions of each of the supporting arms 4.

In various embodiments, the deformation capabilities of each supportingarm 4 may be mainly concentrated on the second portion 20 thereof, whilethe first portions 18 may be designed with a greater bending stiffnessto provide a sufficient support action to a valve prosthesis which iscoupled to the device 1. By way of example, in one embodiment, theportions 18 may be shaped so to have a U-shaped cross section whichoffers a higher bending moment of inertia. According to variousembodiments, the first portion 18 and the second portion 20 areconfigured (e.g., type of material, thickness, or cross-sectionalconfiguration) such that the first portion 18 has a higher bendingstiffness than the second portion 20.

In the various embodiments where the connecting portion 6 is a helicaltrack 10 made (e.g., cut into) a stretch of the tubular element T, theconnector portion 6 allows a displacement of the manipulation axis X1with respect to the supporting formations 4. Such a displacement may beobtained by manipulating the shaft 2. As shown in certain figures, inexemplary embodiments, the helical track 10 extends around the tubularelement three times (e.g., about 1080 degrees). In other embodiments,the helical track extends more or fewer times around the circumferenceof the tubular element T.

The helical track 10 breaks the structural continuity of the tubularelement T at an intermediate position between the shaft 2 and the hub 7from which the supporting arms 4 extend. This may be regarded assubstantially equivalent, so to say, to provide a leaf, helically wound,spring connecting the shaft 2 and the hub 7 and being capable ofproviding an effect which resembles that of a universal joint. Inparticular, as shown in FIG. 2, a displacement of the manipulation axisX1 may be achieved by the deformation of the connection portion 6,wherein various “turns” of the spring-like element defined by thecutting of the helical track 10 are able to separate axially therebyallowing a departure from the rectilinear (i.e., straight) shape of theproximal portion 8.

FIG. 3 shows the supporting device 1, according to an exemplaryembodiment, coupled to an exemplary stentless heart valve prosthesis.The stentless heart valve prosthesis is indicated by the reference V andincludes, in one embodiment, three coapting valve leaflets VL definingthree corresponding commissures C. As shown, the supporting arms 4 ofthe device 1, and in particular the portions 20 thereof, are located ator near the commissures C. As shown, the portions 20 are arranged withinthe orifice defined by the valve V, particularly inside the commissuresC at a position substantially comprised between two adjacent leafletsVL.

In various embodiments, the number of the supporting formations 4 may bechosen so as to be equal to the number of the commissures C of the valveV which is to be coupled to the support device 1. In variousembodiments, the valve prosthesis V may be temporarily attached to thearms 4 by means of suture threads S piercing the commissures C androuted through corresponding eyelets 22, 24. Each suture thread may thenbe passed through the holes 12 (or, more generally, may be routedthrough the hub 7) in order to provide a safe anchoring of the valveprosthesis V to the support device 1. Alternatively, in some embodimentssuch as those depicted in FIG. 7, at least one through hole 120, andpreferably more than one, may be formed on the portion 18 of each of thesupporting arms 4, so that the suture threads S may be routedtherethrough. In other embodiments, both the holes 12 on the hub 7 andthe holes 120 on the portions 18 of the arms 4 are present. In suchembodiments, the suture threads may be passed through either the holes12 or 120, or even both, depending e.g. on specific requests of thepractitioner.

As shown in FIG. 4, in various embodiments, the bending capabilities ofeach of the supporting arms 4 allows for a multiple displacement withinthe support device 1. For example, in addition to the displacement ofthe shaft 2 with respect to the supporting formations 4, that is thedisplacement of the manipulation axis X1 by an angle α₁ with respect toits non-displaced position, an additional displacement may be achievedbetween the manipulation axis X1 and a main axis XV of the valveprosthesis V. The manipulation axis is identified by the reference X1 inits non-displaced position and by the reference X1′ in its displacedposition. This may be achieved because, with reference to FIG. 4, anangle α₂ by which the axis XV may be inclined with respect to themanipulation axis X1 may be the result of the bending of each of thesupporting arms 4, in particular of the portions 20.

As shown in FIG. 5, a manipulation tool 100 may be coupled to thesupport device 1. The manipulation tool 100 may comprise, in variousembodiments, a handle 102 which may be designed with an ergonomicalshape, and a rod 104 which is sized and dimensioned to fit into theshaft 2 and engage in corresponding ones of the connection formations14, 16. In embodiments wherein no such formations 14, 16 are present,the rod 104 is sized and dimensioned so to provide an interference withthe tubular element T, so that a coupling by means of an interferencefit between the rod 104 and the support device 1 (in particular theshaft 2) can be achieved.

For performing the implantation of the valve V, the practitioner maythus vary the position of the manipulation axis X1 with respect to itsnominal (i.e., non-displaced) position and also achieve a displacementof the valve axis XV with respect to the axis X1 depending on thespecific needs during the intervention. For example, apart from ensuringa correct positioning of the valve V with respect to the implantationsite (in the embodiments herein depicted, reference is made to an aorticimplantation site, since the valve V shown in the figures is an aorticvalve prosthesis) the practitioner may also displace the support device1 with respect to the valve V in order to better perform, for example,stitching operations in a specific region of the valve V. After havingreached the implantation site, for example with a retrograde approach,should the combination of the manipulation tool 100 and the supportdevice 1 be of hindrance for the practitioner when stitching the valve Vto the implantation site, the practitioner may displace the shaft 2 andthe valve V with respect to the manipulation axis X1 to clear the wayfor performing such operations.

When the prosthesis V is firmly anchored to the implantation site, thepractitioner may then cut the suture threads S and separate the supportdevice 1 from the prosthesis V by gently pulling the device 1 axiallyaway from the prosthesis V.

In various embodiments, the support device 1 lends itself to variousstructural modifications. For example, in some embodiments, theconnection portion 6 may be provided as a weakened stretch on thetubular element T defined by a plurality of axial slits resulting in theshaft 2 and the hub 7 being connected by a plurality of bridgingelements capable of buckling inwards (and outwards) towards the axis X1in order to provide the desired degree of deformation. Moreover, invarious embodiments, each pair of holes 12 may be replaced by a singlehole, or in alternative, a hook obtained by cutting the corresponding,unfolded shape thereof into the tubular element T and then bending thecut shape outwards of the tubular element T or, as a furtheralternative, by C-shaped openings.

In various embodiment, it is preferred that the material of the tubularelement be a shape memory material such as a super elastic alloy.According to various exemplary embodiments, the tubular element is madeof Nitinol. When Nitinol is employed, the support device 1 may be cut byusing the same techniques as those used for cutting stents, e.g., thevarious components of the support device 1 may be cut into the tubularelement T by means of laser beams. In various embodiments, the structureitself of the support device 1 may be subjected to a large number ofmodifications and various other structures, shapes, patterns may beconferred to each of the components thereof (including the connectionportion 6, the shaft 2, the hub 7 and the supporting formations 4) byvarying the cutting path of the laser beam which are used to cut thetube T.

As shown in FIG. 6, in exemplary embodiments, the connection portion 6′may be provided as an apertured structure. For example, the connectionportion 6′ may be a stent-like structure including a plurality ofapertures 10′ cut into the shaft 2. In such embodiments, the aperturesmay for example have a rectangular shape and may be arranged in radiallyoffset bands. The connection portion 6 may moreover be provided incombination with either arrangement of the holes 12 and/or 120 describedabove. In various exemplary embodiments, the connection portion 6 isprovided as an apertured structure and the holes 12 and/or the holes 120are present.

Without prejudice to the underlying principles of the invention, thedetails and embodiments may vary, even significantly, with respect towhat has been described herein, merely by way of example, withoutdeparting from the scope of the invention as defined by the annexedclaims. Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the above described features.

Various modifications and additions can be made to the exemplaryembodiments discussed without departing from the scope of the presentinvention. For example, while the embodiments described above refer toparticular features, the scope of this invention also includesembodiments having different combinations of features and embodimentsthat do not include all of the described features. Accordingly, thescope of the present invention is intended to embrace all suchalternatives, modifications, and variations as fall within the scope ofthe claims, together with all equivalents thereof.

We claim:
 1. A support device for implantation of a stentless aorticheart valve prosthesis having three leaflets adapted for coapting anddefining three corresponding commissures, the support device including:a shaft defining a manipulation axis, the shaft having a distal portionand a proximal portion having a coupling formation adapted for couplingwith a manipulation tool; and three support formations integrally formedand extending from the distal portion of the shaft, the supportformations disposed with even angular spacing around the manipulationaxis of the shaft, such that each of the support formations correspondto locations of each of the commissures of the stentless heart valveprosthesis; wherein each of the support formations includes a firstportion, the first portion of each support arm extends distally awayfrom the shaft and radially away from the manipulation axis and a secondportion of each support arm is bent with respect to the first portionand extends proximally and parallel to the manipulation axis, the firstportion having a longitudinal length and a first cross-sectionalconfiguration along the longitudinal length, and a second portion,having a second cross-sectional configuration, and extending from thefirst portion, the first cross-sectional configuration along thelongitudinal length of the first portion having a U-shape and configuredsuch that the first portion has a greater bending moment of inertia thanthe second portion; wherein the shaft includes a flexible portionconnecting the shaft and the support formations to permit a displacementof the manipulation axis with respect to the support formations, theflexible portion consisting of a helical track extending about acircumference of the shaft; and wherein the shaft, the plurality ofsupport formations and the flexible portion are integrally formed from asingle tubular element.
 2. The support device claim 1, wherein thetubular element is made of a shape memory material.
 3. The supportdevice of claim 1, wherein the support formations departing from a hubon the shaft are disposed adjacent to the connection portion.
 4. Thesupport device of claim 1, wherein the first portion of each support armalso extends in an axial direction from the distal portion of the shaft.5. The support device of claim 1, wherein the flexible portion consistsof a helical track extending at least three times around the shaft. 6.The support device of claim 1, further comprising a manipulation toolhaving a feature for releasably coupling with the coupling formation onthe proximal end of the shaft and the manipulation tool having anergonomic handle.
 7. The support device of claim 1, wherein the shaftincludes a plurality of through holes distributed and axially staggeredaround the shaft, such that each through hole is disposed at a positionaligned with a corresponding supporting formation.
 8. The support deviceof claim 7, wherein each of the through holes is disposed on the hub. 9.The support device of claim 1, wherein each support arm includes a firsteyelet located at a position between the first and second portions and asecond eyelet located at a free end of the second portion.
 10. Thesupport device of claim 1, wherein the stentless aortic heart valveprosthesis is coupled to the support device with suturing coupling eachof the commissures of the stentless heart valve prosthesis to acorresponding support arm.
 11. A support device for implantation of astentless heart valve prosthesis having three leaflets adapted forcoapting and defining three corresponding commissures, the supportdevice including: a shaft defining a manipulation axis, the shaft havinga proximal portion and a distal portion; and three support formationsintegrally formed and extending from the distal end of the shaft, thesupport formations disposed with even angular spacing around themanipulation axis of the shaft, such that each of the support formationscorrespond to locations of each of the commissures of the stentlessheart valve prosthesis; wherein each of the support formations includesa first proximal portion extending from the distal end of the shaft withboth a radial and an axial extension component, the axial extensioncomponent extending distally with respect to the shaft, the radialextension component extends radially away from the manipulation axis,and a second distal portion having a first end extending from the firstproximal portion and having a second end that is free and that extendsproximally with respect to the first end, the second distal portionextending parallel to the shaft and radially aligned with the firstproximal portion, and the second distal portion of each support arm isbent with respect to the first proximal portion and extends proximallyand parallel to the manipulation axis; wherein the shaft includes aflexible portion connecting the shaft and the support formations topermit a displacement of the manipulation axis with respect to thesupport formations; and wherein the shaft, the plurality of supportformations and the flexible portion are integrally formed from a singletubular element.
 12. The support device of claim 11, wherein each of thefirst proximal portions has a first cross-sectional configuration andeach of the second distal portions has a second cross-sectionalconfiguration, the first cross-sectional configuration having a greaterbending moment than the second cross-sectional configuration.
 13. Thesupport device of claim 12, wherein the first proximal portion has aU-shaped cross section.
 14. The support device of claim 11, wherein eachof the first proximal portions has a first dimension and each of thesecond distal portions has a second dimension, such that the firstproximal portion has a greater bending stiffness than the second distalportion.
 15. The support device of claim 11, further comprising amanipulation tool having a feature for releasably coupling with thecoupling formation on the distal end of the shaft and the manipulationtool having an ergonomic handle.
 16. The support device of claim 11,wherein the stentless aortic heart valve prosthesis is coupled to thesupport device with suturing coupling each of the commissures of thestentless heart valve prosthesis to a corresponding support arm.
 17. Thesupport device of claim 11, wherein the coupling formation is a helicaltrack extending around a circumference of the shaft.
 18. The supportdevice of claim 17, wherein the helical track extends at least threetimes around the circumference of the shaft.